2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
8 #ifndef NOTIFICATION_THREAD_INTERNAL_H
9 #define NOTIFICATION_THREAD_INTERNAL_H
11 #include <common/compat/socket.hpp>
12 #include <common/credentials.hpp>
13 #include <common/payload.hpp>
14 #include <lttng/notification/channel-internal.hpp>
15 #include <lttng/ref-internal.hpp>
18 #include <urcu/rculfhash.h>
20 #include <urcu/call-rcu.h>
21 #include "notification-thread.hpp"
23 struct lttng_evaluation;
24 struct notification_thread_handle;
28 enum lttng_domain_type domain;
38 * Hashtable containing back-refs (weak) to all channels in this session.
39 * The hashtable's key is a hash of (struct channel_key) and
40 * the value is of type (struct channel_info *).
42 struct cds_lfht *channel_infos_ht;
43 struct lttng_session_trigger_list *trigger_list;
44 /* Node in the notification thread state's sessions_ht. */
45 struct cds_lfht_node sessions_ht_node;
47 * Weak reference to the thread state's sessions_ht. Used for removal on
50 struct cds_lfht *sessions_ht;
51 uint64_t consumed_data_size;
53 /* Whether a rotation is ongoing for this session. */
55 /* Identifier of the currently ongoing rotation. */
58 /* call_rcu delayed reclaim. */
59 struct rcu_head rcu_node;
63 struct channel_key key;
67 * A channel info holds a reference (lttng_ref) on session_info.
68 * session_info, in return, holds a weak reference to the channel.
70 struct session_info *session_info;
71 /* Node in the notification thread state's channels_ht. */
72 struct cds_lfht_node channels_ht_node;
73 /* Node in the session_info's channels_ht. */
74 struct cds_lfht_node session_info_channels_ht_node;
75 /* call_rcu delayed reclaim. */
76 struct rcu_head rcu_node;
80 * Facilities to carry the different notifications type in the action
81 * processing code path.
83 struct lttng_event_notifier_notification {
84 uint64_t tracer_token;
85 enum lttng_domain_type type;
86 size_t capture_buf_size;
90 struct notification_client_list_element {
91 struct notification_client *client;
92 struct cds_list_head node;
96 * Thread safety of notification_client and notification_client_list.
98 * The notification thread (main thread) and the action executor
99 * interact through client lists. Hence, when the action executor
100 * thread looks-up the list of clients subscribed to a given
101 * condition, it will acquire a reference to the list and lock it
102 * while attempting to communicate with the various clients.
104 * It is not necessary to reference-count clients as they are guaranteed
105 * to be 'alive' if they are present in a list and that list is locked. Indeed,
106 * removing references to the client from those subscription lists is part of
107 * the work performed on destruction of a client.
109 * No provision for other access scenarios are taken into account;
110 * this is the bare minimum to make these accesses safe and the
111 * notification thread's state is _not_ "thread-safe" in any general
114 struct notification_client_list {
115 pthread_mutex_t lock;
117 struct lttng_condition *condition;
118 /* List of triggers that have an identical condition than `condition`. */
119 struct cds_list_head triggers_list;
120 struct cds_list_head clients_list;
121 /* Weak reference to container. */
122 struct cds_lfht *notification_trigger_clients_ht;
123 struct cds_lfht_node notification_trigger_clients_ht_node;
124 /* call_rcu delayed reclaim. */
125 struct rcu_head rcu_node;
128 struct notification_client {
130 * Nests within the notification_client_list lock.
132 * Protects the outbound communication and the active flag which
133 * is used by both the notification and action executor threads.
135 * The remaining fields of the object can be used without any
136 * synchronization as they are either immutable (id, creds, version) or
137 * only accessed by the notification thread.
139 pthread_mutex_t lock;
140 notification_client_id id;
142 /* Client protocol version. */
143 uint8_t major, minor;
148 * Indicates if the credentials and versions of the client have been
153 * Conditions to which the client's notification channel is subscribed.
154 * List of struct lttng_condition_list_node. The condition member is
155 * owned by the client.
157 struct cds_list_head condition_list;
158 struct cds_lfht_node client_socket_ht_node;
159 struct cds_lfht_node client_id_ht_node;
162 * If a client's communication is inactive, it means that a
163 * fatal error has occurred (could be either a protocol error or
164 * the socket API returned a fatal error). No further
165 * communication should be attempted; the client is queued for
169 int current_poll_events;
172 * During the reception of a message, the reception
173 * buffers' "size" is set to contain the current
174 * message's complete payload.
176 struct lttng_payload payload;
177 /* Bytes left to receive for the current message. */
178 size_t bytes_to_receive;
179 /* FDs left to receive for the current message. */
181 /* Type of the message being received. */
182 enum lttng_notification_channel_message_type msg_type;
184 * Indicates whether or not credentials are expected
189 * Indicates whether or not credentials were received
193 /* Only used during credentials reception. */
194 lttng_sock_cred creds;
198 * Indicates whether or not a notification addressed to
199 * this client was dropped because a command reply was
202 * A notification is dropped whenever the buffer is not
205 bool dropped_notification;
207 * Indicates whether or not a command reply is already
208 * buffered. In this case, it means that the client is
209 * not consuming command replies before emitting a new
210 * one. This could be caused by a protocol error or a
211 * misbehaving/malicious client.
213 bool queued_command_reply;
214 struct lttng_payload payload;
217 /* call_rcu delayed reclaim. */
218 struct rcu_head rcu_node;
221 enum client_transmission_status {
222 CLIENT_TRANSMISSION_STATUS_COMPLETE,
223 CLIENT_TRANSMISSION_STATUS_QUEUED,
224 /* Communication failure. */
225 CLIENT_TRANSMISSION_STATUS_FAIL,
227 CLIENT_TRANSMISSION_STATUS_ERROR,
230 bool notification_client_list_get(struct notification_client_list *list);
232 void notification_client_list_put(struct notification_client_list *list);
234 /* Only returns a non-zero value if a fatal error occurred. */
235 typedef int (*report_client_transmission_result_cb)(
236 struct notification_client *client,
237 enum client_transmission_status status,
240 int notification_client_list_send_evaluation(
241 struct notification_client_list *list,
242 const struct lttng_trigger *trigger,
243 const struct lttng_evaluation *evaluation,
244 const struct lttng_credentials *source_object_creds,
245 report_client_transmission_result_cb client_report,
248 int notification_thread_client_communication_update(
249 struct notification_thread_handle *handle,
250 notification_client_id id,
251 enum client_transmission_status transmission_status);
254 * Takes ownership of the payload if present.
256 struct lttng_event_notifier_notification *lttng_event_notifier_notification_create(
257 uint64_t tracer_token,
258 enum lttng_domain_type domain,
260 size_t payload_size);
262 void lttng_event_notifier_notification_destroy(
263 struct lttng_event_notifier_notification *event_notifier_notification);
265 #endif /* NOTIFICATION_THREAD_INTERNAL_H */